make sprintf("%g",...) threadsafe; only taint its result iff the

formatted result looks nonstandard

p4raw-id: //depot/perl@4130

2 files changed, 14 insertions, 5 deletions

diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod
index 0d47260e10..995a671110 100644
--- a/pod/perlfunc.pod
+++ b/pod/perlfunc.pod
@@ -4120,6 +4120,13 @@ If C<use locale> is in effect, the character used for the decimal
 point in formatted real numbers is affected by the LC_NUMERIC locale.
 See L<perllocale>.
 
+To cope with broken systems that allow the standard locales to be
+overridden by malicious users, the return value may be tainted
+if any of the floating point formats are used and the conversion
+yields something that doesn't look like a normal C-locale floating
+point number.  This happens regardless of whether C<use locale> is
+in effect or not.
+
 If Perl understands "quads" (64-bit integers) (this requires
 either that the platform natively supports quads or that Perl
 has been specifically compiled to support quads), the characters
diff --git a/pod/perlguts.pod b/pod/perlguts.pod
index 93d4bd70c4..af12297ec3 100644
--- a/pod/perlguts.pod
+++ b/pod/perlguts.pod
@@ -3649,24 +3649,26 @@ Like C<sv_usepvn>, but also handles 'set' magic.
 
 	void	sv_usepvn_mg (SV* sv, char* ptr, STRLEN len)
 
-=item sv_vcatpvfn(sv, pat, patlen, args, svargs, svmax, used_locale)
+=item sv_vcatpvfn
 
 Processes its arguments like C<vsprintf> and appends the formatted output
 to an SV.  Uses an array of SVs if the C style variable argument list is
-missing (NULL).  Indicates if locale information has been used for formatting.
+missing (NULL).  When running with taint checks enabled, indicates via
+C<maybe_tainted> if results are untrustworthy (often due to the use of
+locales).
 
 	void	sv_catpvfn (SV* sv, const char* pat, STRLEN patlen,
 			    va_list *args, SV **svargs, I32 svmax,
-			    bool *used_locale);
+			    bool *maybe_tainted);
 
-=item sv_vsetpvfn(sv, pat, patlen, args, svargs, svmax, used_locale)
+=item sv_vsetpvfn
 
 Works like C<vcatpvfn> but copies the text into the SV instead of
 appending it.
 
 	void	sv_setpvfn (SV* sv, const char* pat, STRLEN patlen,
 			    va_list *args, SV **svargs, I32 svmax,
-			    bool *used_locale);
+			    bool *maybe_tainted);
 
 =item SvUV